The mountainous forests in arid regions, being sensitive to climate change, are one of the key research topics related to the mechanism of interaction between climate and the terrestrial ecosystem. In this study, the ...The mountainous forests in arid regions, being sensitive to climate change, are one of the key research topics related to the mechanism of interaction between climate and the terrestrial ecosystem. In this study, the spatial distribution of a mid-mountain forest and its environmental factors were investigated by using a combination of remote sensing technology, field survey, climate indices and soil nutrient analysis in the Sangong River watershed of the northern Tianshan Mountains. The forest （Picea schrenkiana） was distributed between 1,510 and 2,720 m asl. Tree height and diameter at breast height （DBH） exhibited a bi-modal pattern with increasing elevation, and rested at 2,450 and 2,250 m asl, respectively. The two maxima of DBH appeared at 2,000 and 2,550 m asl, and the taller trees were observed at 2,100 and 2,600 m asl. For the annual mean temperature, the difference was approximately 5.8℃ between the lowest and the highest limits of the forest, and the average decreasing rates per hundred meters were 0.4g℃ and 0.55℃ with increasing altitude between 1,500 and 2,000 m asl and above 2,000 m asl, respec- tively. The annual precipitation in the forest zone first increased and then decreased with the increase of altitude, and the maximum value was at 2,000 m asl. For per hundred meters, the annual precipitation increased with the rate of 31 mm between 1,500 and 2,000 m asl and decreased by 7.8 mm above 2,000 m asl. The SOM, TN and TP were high between 2,000 and 2,700 m asl and low at the lower and upper forest limits. The minimum CaCO3 con- centration, pH value and EC coincided with the maximum precipitation belt at 2,000 m asl. The SOM, TN and TP were high in the topsoil （0-10 cm） and differed significantly from the values observed in the deep soil layers （〉10 cm）. The soil nutrients exhibited spatial heterogeneity and higher aggregation in the topsoil. In conclusion, soil and climate are closely related to each other, working synergistically to determine the development and spatial distribution of the mid-mountain forest in the study area. The order of the importance of environmental factors to forest development in this study is as follows： soil nutrients〉precipitation〉elevation〉temperature.展开更多
The steep North to South (N-S) gradient and complex topography markssignificant variations in the spatial and temporal patterns of climatic variationsurrounding within a few distances in the Nepal Himalayas. Hence,to ...The steep North to South (N-S) gradient and complex topography markssignificant variations in the spatial and temporal patterns of climatic variationsurrounding within a few distances in the Nepal Himalayas. Hence,to validate climatic linkages between the stations under two distinct topographicconditions, the study examines the observational climatic data from106m a.s.l. and 1801m a.s.l., as a representative station from a plain andhilly area. Different statistical tools including Pearson correlation analysisand a best-fit regression model were applied to analyze climate data. Theanalysis of 13129 daily average temperature records and 13147 daily totalprecipitation records showed that the variation in their sum and average ofdaily, five days, ten days, and monthly values between the stations in thedifferent elevations marked significantly.Despite these variations, temperaturerecords are measured to be consistent in different altitudes and stronglycorrelated. The precipitation data showed a comparatively weaker correlation.The coefficients (0.85-1.6) with R2>0.50 in the regression models forthe lower elevation and higher elevation station in the mid-mountain regionexcept for the monsoon season. It indicated a similar fluctuation of temperaturebetween these two stations in the respective area. The strong degreeof association and the change of climatic parameters in different rangeand elevations indicate the possibilities of using climatic data from Terai torepresent the Mid-mountain region of central Nepal.展开更多
基金funded by the National Natural Science Foundation of China (41271126)the Ph.D. Research Foundation of Guizhou Normal Universitythe Science and Technology Foundation of Guizhou Province (J[2014]2126)
文摘The mountainous forests in arid regions, being sensitive to climate change, are one of the key research topics related to the mechanism of interaction between climate and the terrestrial ecosystem. In this study, the spatial distribution of a mid-mountain forest and its environmental factors were investigated by using a combination of remote sensing technology, field survey, climate indices and soil nutrient analysis in the Sangong River watershed of the northern Tianshan Mountains. The forest （Picea schrenkiana） was distributed between 1,510 and 2,720 m asl. Tree height and diameter at breast height （DBH） exhibited a bi-modal pattern with increasing elevation, and rested at 2,450 and 2,250 m asl, respectively. The two maxima of DBH appeared at 2,000 and 2,550 m asl, and the taller trees were observed at 2,100 and 2,600 m asl. For the annual mean temperature, the difference was approximately 5.8℃ between the lowest and the highest limits of the forest, and the average decreasing rates per hundred meters were 0.4g℃ and 0.55℃ with increasing altitude between 1,500 and 2,000 m asl and above 2,000 m asl, respec- tively. The annual precipitation in the forest zone first increased and then decreased with the increase of altitude, and the maximum value was at 2,000 m asl. For per hundred meters, the annual precipitation increased with the rate of 31 mm between 1,500 and 2,000 m asl and decreased by 7.8 mm above 2,000 m asl. The SOM, TN and TP were high between 2,000 and 2,700 m asl and low at the lower and upper forest limits. The minimum CaCO3 con- centration, pH value and EC coincided with the maximum precipitation belt at 2,000 m asl. The SOM, TN and TP were high in the topsoil （0-10 cm） and differed significantly from the values observed in the deep soil layers （〉10 cm）. The soil nutrients exhibited spatial heterogeneity and higher aggregation in the topsoil. In conclusion, soil and climate are closely related to each other, working synergistically to determine the development and spatial distribution of the mid-mountain forest in the study area. The order of the importance of environmental factors to forest development in this study is as follows： soil nutrients〉precipitation〉elevation〉temperature.
文摘The steep North to South (N-S) gradient and complex topography markssignificant variations in the spatial and temporal patterns of climatic variationsurrounding within a few distances in the Nepal Himalayas. Hence,to validate climatic linkages between the stations under two distinct topographicconditions, the study examines the observational climatic data from106m a.s.l. and 1801m a.s.l., as a representative station from a plain andhilly area. Different statistical tools including Pearson correlation analysisand a best-fit regression model were applied to analyze climate data. Theanalysis of 13129 daily average temperature records and 13147 daily totalprecipitation records showed that the variation in their sum and average ofdaily, five days, ten days, and monthly values between the stations in thedifferent elevations marked significantly.Despite these variations, temperaturerecords are measured to be consistent in different altitudes and stronglycorrelated. The precipitation data showed a comparatively weaker correlation.The coefficients (0.85-1.6) with R2>0.50 in the regression models forthe lower elevation and higher elevation station in the mid-mountain regionexcept for the monsoon season. It indicated a similar fluctuation of temperaturebetween these two stations in the respective area. The strong degreeof association and the change of climatic parameters in different rangeand elevations indicate the possibilities of using climatic data from Terai torepresent the Mid-mountain region of central Nepal.
